Supercapacitors (also termed as ultracapacitors) are being projected as potential devices that could enable major advances in energy storage. Supercapacitors are governed by the same physics as conventional capacitors but utilize high-surface-area electrodes and thinner dielectrics to achieve greater capacitances allowing energy densities greater than those of conventional capacitors and power densities greater than those of batteries. Supercapacitors can be divided into three general classes, namely electrical-double-layer capacitors, pseudocapacitors and hybrid capacitors. Each class is characterized by its unique mechanism for charge storage, namely faradaic, non-faradaic and the combination of the two. Faradaic processes, such as oxidation-reduction reactions, involve the transfer of charge between electrode and electrolyte as in a battery electrode while a non-faradaic mechanism does not use a chemical mechanism and rather charges are distributed on surfaces by physical processes that do not involve the making or braking of chemical bonds “similar to electrical” double-layer. A hybrid supercapacitor combines a battery electrode where the energy is stored in chemical form and an electrical-double-layer electrode where the energy is stored in physical form. A PbO2/Activated Carbon supercapacitor comprises a positive plate akin to a lead acid cell and a high surface-area activated carbon electrode as negative plate. The charge-discharge reactions at the positive and negative plates of such a hybrid supercapacitors are as follows.(+) plate: PbSO4+2H2OPbO2+H2SO4+2H++2e−(−) plate: 2C+2H++2e−2(C-Hads+)dl 
Accordingly, the net charge-discharge reactions for the hybrid supercapacitor can be written as follows.PbSO4+2H2O+2CPbO2+H2SO4+2(C-Hads+)dl 
The (+) plate is realized by electrochemical plating and cycling in sulphuric acid/perchloric acid while the (−) plate is prepared by pasting activated carbon onto a lead sheet. The said hybrid supercapacitor stores energy both in chemical and physical forms.
The hybrid capacitors known in the prior art employ conventional PbO2 plates that require sizing and mixing of the active materials of—appropriate compositions, pasting, drying, curing and formation. Such electrodes are not fully amenable to fast charge/discharge processes desirous of a capacitor.